JP2020051619A - Device and method for filling pressurized gas tanks - Google Patents

Abstract

To provide a device for filling vehicle pressurized hydrogen tanks.SOLUTION: A device (1) comprises: a liquefied gas source (2); a transfer circuit comprising two parallel transfer lines each having an upstream end (3) linked to the liquefied gas source; and at least two separate downstream ends (4) intended to be each removably connected to a tank (22) to be filled. Each of the two transfer lines comprises: a pump (5); a unit (6) for evaporating pumped fluid; a branch (13) for bypassing the evaporating unit; and a set of distribution valves (7, 8) configured to control the flow of fluid pumped and distributed between the evaporating unit and the bypassing branch. The device further comprises a set of buffer storages (9, 10) which are connected in parallel to each of the two transfer lines via the set of valves.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an apparatus for filling a pressurized gas tank.

  More specifically, the present invention relates to an apparatus for filling a pressurized gas tank, specifically a vehicle pressurized hydrogen tank, wherein the apparatus comprises a liquefied gas source and each linked to a liquefied gas source. A transfer circuit comprising two parallel transfer lines having upstream ends, each transfer line having a downstream end intended to be removably connected to the tank to be filled.

  Hydrogen gas refueling stations that use a liquid hydrogen source are known. These known devices use cold air from liquid hydrogen to produce a pre-cooled pressurized gas for rapid filling, without excessively increasing the temperature of the gas in the tank during filling. To be able to use.

  See, for example, US Pat. See Faste and J Hansel, "Quick Fill Hydrogen Fuel Station for Fuel Cell Buses" (12th World Energy Congress, Enhancing Hydrogen Energy 2 p. 1629-1642). D. E. FIG. Reference is also made to the paper by Danney et al., "Hydrogen Vehicle Fuel Stations" (Evolution in Cryogenics Vol. 41, 1996).

  These known arrangements do not make it possible to guarantee both the sufficient performance of the installation and its modularity.

  It is an object of the present invention to overcome all or some of the disadvantages of the prior art described above.

  For this purpose, the device according to the invention, and also according to the general definition given by the above preamble, consists essentially of two transfer lines each comprising a pump and an evaporating fluid to be pumped. A unit for bypassing the evaporation unit, and a set of distribution valves configured to control the flow of fluid delivered and distributed between the evaporation unit and the bypass branch, The apparatus further comprises a set of buffer storage devices, wherein the buffer storage devices are connected in parallel to each of the two transfer lines via a set of valves.

Further, embodiments of the invention can include one or more of the following features:
A set of buffer storage devices is connected to each transfer line between the evaporation unit and a point of mixing between the fluid passing through the evaporation unit and the fluid passing through the bypass branch,
A set of buffer storage devices is connected to each transfer line via a respective expansion valve,
The set of distribution valves of each transfer line comprises a first distribution valve located downstream of the evaporation unit and upstream of the point of mixing with the fluid passing through the bypass branch, the set of distribution valves comprising: Providing a second distribution valve in the branch;
The set of buffer storage devices comprises two or more buffer storage devices connected in parallel to each transfer line, each buffer storage device being connected to each transfer line via a respective separation valve;
The transfer circuit comprises a connection duct linking the two transfer lines to the outlets of the two pumps, said connection duct comprising a separation valve;
-The two transfer lines comprise at least one thermally insulated portion;
The two transfer lines comprise, in particular, at least one pressure sensor and / or at least one temperature sensor measuring the pressure and the temperature, respectively, in close proximity to the downstream end;
During at least part of the filling operation, in particular when the defined gas flow is less than or equal to the maximum flow of the pump;
The gas flow transferred to the tank is formed solely by the gas flow provided by the pump and distributed between the evaporation unit and the bypass branch,
The flow rate defined for filling the tank is variable between 0 and 100 g / sec, in particular between 10 and 60 g / sec;
The pump is a variable speed pump, the gas flow transferred to the tank during filling is controlled by controlling the speed of the pump and possibly the amount of gas provided by a set of buffer storage devices; ,
The temperature of the pressurized gas transferred to the tank during filling, the relative distribution between the relatively hot gas passing through the evaporation unit and the relatively cold gas passing through the bypass branch, and possibly the buffer Controlled by managing the amount of relatively hot gas coming from the set of storage devices,
The additional gas flow provided by the set of buffer storage devices is controlled in response to a pressure signal measured at the downstream end of the transfer line;
The set of buffer storage devices comprises a number of buffer storage devices connected in parallel to each transfer line and is used sequentially according to a cascade process to provide gas to the transfer lines.

  The present invention also relates to a method of filling at least one pressurized gas tank with a defined gas flow rate at a defined temperature to establish a fill determination gradient in the tank, the method comprising the above or following features. A filling device according to any one of them is used.

According to other possible properties:
Gas flow is variable and modified over time,
During at least a part of the filling operation, in particular when the defined gas flow is greater than the maximum flow of the pump, the gas flow transferred to the tank is firstly provided by the pump and the evaporation unit and the bypass branch And secondly, the sum of the additional gas flows provided by the set of buffer storage devices.
The method fills the tank with a gas flow comprising the sum of the gas flows provided by the pumps of the two transfer lines by transferring the gas flow from one transfer line to another; Including the step of
The method comprises a relative distribution between a relatively hot gas passing through the evaporation unit and a relatively cold gas passing through the bypass branch before or when filling is started. Cooling the transfer line, optionally comprising the transfer of gas at a defined temperature controlled by managing the amount of relatively hot gas coming from the set of buffer storage devices.
The step of cooling the transfer line comprises opening the distribution valve opening between the evaporation unit and the bypass branch, possibly according to an “open loop” (“forward feed”) type control and / or transferring Performed by controlling the additional gas flow provided by the set of buffer storage devices according to a control loop based on the temperature measured in the line;
The step of cooling the transfer line comprises flowing outward or to a unit for returning gas transferred at a defined temperature controlled in the transfer line to be cooled;

  The invention may also relate to any alternative device or method comprising any combination of the above or below features within the scope of the claims.

  Other features and advantages will become apparent from reading the following description with reference to the drawings.

FIG. 1 shows a schematic and partial view illustrating the structure and an example of operation of an exemplary device according to the present invention. FIG. 2 shows a graph of the evolution of parameters according to an example of a possible filling according to the invention.

Detailed description

  An apparatus 1 for filling a pressurized gas tank (particularly a vehicle pressurized gas hydrogen tank) shown in FIG. 1 includes a liquefied gas source 2. The liquefied gas source comprises, for example, at least a vacuum adiabatic liquefied gas storage device and / or a liquefied gas source (liquefier or any other suitable device).

  In the case where the gas is hydrogen (H2), for simplicity, the state of the fluid will be described by the customary term "gas" or "fluid", the latter being the pressure of the fluid It should be noted that, depending on, it will actually be a supercritical fluid.

  The apparatus 1 comprises a transfer circuit 3 comprising two parallel fluid transfer lines, each having an upstream end 3 linked to a liquefied gas source 2 for drawing liquefied gas from the liquefied gas source 2. doing. Each transfer line has a downstream end 4 intended to be removably connected to a tank 22 to be filled (if necessary, for example, via a flexible part provided with suitable quick connectors and flaps). Respectively.

  Although the example of FIG. 1 has two transfer lines, it should be noted that there can be more than two transfer lines.

  Each of the two transfer lines includes a pump 5, an evaporation unit 6 for evaporating the fluid to be sent out, and a bypass branch 13 for selectively bypassing the evaporation unit 6.

  In addition, each line is pumped out, the evaporating unit 6 (where the fluid is heated and evaporated, and therefore relatively hot and at a relatively high pressure) and the bypass branch 13 (when leaving the pump 5 the fluid is (Which is substantially thermodynamic and therefore relatively cool) comprises a set of distribution valves 7, 8 configured to control the flow of fluid distributed between them.

  Downstream of the evaporation unit 6, the two parallel parts meet at a point where the two relatively hot and cold fluids mix.

  The set of distribution valves 7, 8 in each transfer line is, for example, a first distribution valve 7, which is preferably located downstream of the evaporating unit 6 and upstream of the point of mixing with the fluid passing through the bypass branch 13. Have. The set of distribution valves 7, 8 may further comprise a second distribution valve 8 in the bypass branch 13 (upstream of the point of mixing).

  Of course, any other distribution system can be envisaged, in particular a three-way valve system.

  Since the distribution valve 7 is positioned downstream of the heating unit 6 and upstream of the point of mixing, this makes it possible to use a valve operating at ambient temperature (non-cold), which is relatively Manage low flow rates. This increases the reliability of the equipment and limits its cost.

  The circuit also comprises an upstream valve 23 located in each transfer line, preferably between the outlet of the pump 5 and before the evaporation and bypass branch.

  Conventionally, it is also possible to control the temperature of the fluid at the outlet (end 4) of the filler, for example via this mixing, in order to maintain a defined temperature, in particular between -33 ° C and -40 ° C it can.

  This makes it possible to obtain a gas stream at the defined pressure and temperature provided for filling the tank 22, while limiting heating in the latter.

  Evaporation unit 6 is, for example, a heater that heats an exchanger that provides heat exchange of liquid hydrogen with a heating source (air or another heating element).

  Apparatus 1 further comprises one or more pressurized gas buffer storage devices 9, 10 connected in parallel to each of the transfer lines via respective sets of valves 11-16.

  This configuration of providing a pump 5 for each transfer line (for each transfer line for filling the tank 22) has many advantages over known systems. This allows the station to be completely modular (some possible simultaneous filling operations, the possibility of adding or removing transfer lines without affecting the performance of another line, etc.).

  Furthermore, this solution improves the performance of the device. Indeed, according to this arrangement, each pump 5 of the transfer line therefore has better capacity and energy efficiency, especially at low pressures.

  Indeed, one dedicated pump 5 ("dispenser") per transfer line can reduce the performance loss, pump 5 wear, and Joule-Thomson expansion loss at the pressure required by the tank 22 being filled. Allows to provide hydrogen.

  Thus, between 200 and 900 bar (instead of a range between 700 and 900 bar when a single pump is directly connected to the buffer storage and used for several transfer lines) Each pump 5 can be fully used in areas of use that provide its best energy and capacity efficiency at relatively low pressures. Such low pressure operation enabled by the present invention can reduce the energy consumption of the pump by as much as 50%.

  As shown in FIG. 1, the buffer storage devices 9, 10 are preferably arranged between the evaporation unit 6 and a mixing point between the fluid passing through the evaporation unit 6 and the fluid passing through the bypass branch 13. Connected to each transfer line.

  For example, a buffer storage device 9, 10 can be connected in parallel to each transfer line via a respective expansion valve 15, 16. In addition, each buffer storage device 9,10 can comprise a respective isolation valve 11,12 located between the inlet / outlet of the storage device 9,10 and each expansion valve 15,16.

  These storage device isolation valves 11, 12, 25, 14, which are separated for each dispenser transfer line, allow the buffer storage to be shared while maintaining the transfer lines independently.

  As shown in FIG. 1, the transfer circuit 3 can advantageously comprise at least one connection duct 17 linking two (or more) transfer lines at the outlet of the pump 5. The connection duct 17 includes, for example, a separation valve 18. This connection duct and its valve 18 allow, where applicable, to share (add) the outgoing flow when needed (eg when filling large tanks and / or when the pump fails). To

  As shown in the diagram in FIG. 1, at least a portion 19 of each transfer line can be thermally insulated (not necessarily under vacuum and / or cooling). Furthermore, each line may comprise at least one pressure sensor 20 and / or at least one temperature sensor 21 for measuring the pressure / temperature there, especially near the downstream end for connection to the tank 22. it can.

  All or some of the valves may be, for example, valves managed by an electronic controller 24 comprising a microprocessor and / or computer provided with a data acquisition, storage and processing system. To acquire data and control and manage these units, the controller 24 can be linked to sensors and various other units of the device (in particular the pump 5).

  As illustrated in FIG. 2, by way of non-limiting example, the filling of the tank is preferably generated according to a (pre-) defined gradient filling. For example, a set of pumps 5 and valves is managed, for example, to provide a pre-determined pressure increase rate in the tank (P22 = pressure in the tank), which is mainly linear. For example, the pressure P4 measured in the transfer duct 4 (and representing the pressure P22 in the tank 22) is controlled to increase linearly over time. This can be obtained by controlling the amount M22 in the container 22 over time T, so that the gas flow Q is transferred over time. This flow rate is defined according to the filling state (amount, tank capacity, temperature, etc.).

  The transfer of the required gas flow can be provided by the pump 5 and, in some cases, can be captured by the additional gas flow provided by the buffer storage devices 9,10.

  In a typical filling case, the tank must be filled with 5-7 kg of hydrogen at an ambient temperature of 15 [deg.] C after a few minutes (e.g. 3 minutes), e.g. according to the filling gradient defined by the filling protocol.

  For example, at the start of filling, the pump 5 may be sufficient to provide the required flow rate to fill the vehicle alone. Depending on the pressure gradient, this flow increases from zero from the start of filling to the maximum flow of the pump.

  The pressure gradient is managed (acquired) by, for example, modulating the speed of the pump 5. The pressure provided by the pump 5 is the pressure required at the end of the transfer line by the tank 22 to be filled. This pressure can typically be around 50 to 300 bar, depending on the initial pressure of the tank 22.

  The hydrogen passes through the heated evaporation unit 6 while allowing the bypass branch 13 to transfer cryogenic hydrogen from the pump 5 at its outlet temperature.

  To reach the target gas temperature at the downstream end 4, the openings of the two valves 7, 8 can be managed to reach a proper distribution.

  If the line is too hot (measured temperature 21 exceeds the target temperature), in particular, the valve 7 on the “hot” side can be completely closed and the valve 8 on the “cold” side, for example, It can be fully opened to allow a 100% cold flow rate for cooling.

  If the line is too cold, the cold flow / hot flow ratio can be adjusted by valves 7, 8 between 30% and 50%, for example, depending on the performance of the pump 5 and / or ambient temperature. .

  When the tank 22 is filled, the filling flow rate can be increased, and in particular can exceed the volume of the pump 5.

  The controller can detect 20 the lack of pressure in the line with respect to the target pressure, and can open the valves 11, 15 of the buffer storage device to overcome this.

  This means controlling the flow rate of the pump, and the flow rate provided by the buffer storage device can be controlled to provide a pressure set point measured at the transfer line (particularly at the downstream end).

  In this configuration, the pump 5 can be at its maximum flow (maximum speed) and the pressure gradient is managed by the expansion valve 15.

  The pressure provided by the pump 5 (such as the pressure in the transfer line) increases until a filling pressure limit (for example 700 to 850 bar) is reached. Where applicable, the storage devices 9, 10 can be used as a cascade (the valves 11, 12; 25, 14 associated with the storage devices switch from one storage device to another) To allow).

  The hydrogen provided by the buffer storage devices 9, 10 is matched with the flow coming from the pump 5 after expansion at the corresponding valves 15, 16. Valves 7 and 8 constantly control the temperature of the provided gas.

  The flow rate provided in this second filling stage may be higher, for example, approximately 25-45 g / s, for example, reaching a peak of 60 g / s.

  The hot gas flow provided by the buffer storage devices 9, 10 is also variable and large, and the ratio between the cold gas and the hot gas provided by the pump 5 is greater than during the start of filling. This ratio can vary, for example, between 30% and 100%, depending on the total filling flow rate.

  When filling is completed, the pump 5 can be used to fill the storage devices 9, 10 to its nominal pressure. All of the pumped hydrogen can be heated to the storage pressure (400-500 bar for medium pressure buffer storage, 700-1000 bar for high pressure buffer storage).

  In some cases, filling requires only a low flow rate, which is low enough to be completely provided by the pump 5 (eg a small tank with a volume less than 4 kg of hydrogen). When the ambient temperature is (extremely) high, for example above 30 ° C. or 40 ° C., a low flow filling can also be provided.

  In this case, the expansion valves 15, 16 can remain closed during filling. The pressure gradient can be completely controlled by the speed of the pump 5. The cold flow / hot flow ratio is regulated by corresponding valves 7, 8 and can vary, for example, between 30% and 50%, except for cooling the line as described above.

  In the case of the high flow rate required to fill a large tank 22 (such as a bath tank storing more than 10 kg of hydrogen), the required flow rate and the required cooling power are relatively large. Such rapid filling is always possible by providing a high filling flow rate in the transfer line. This can be achieved by using two pumps 5 and controlling the appropriate valves, in particular by opening the valve 18 of the connecting duct 17.

  Thus, this layout doubles the volume of the transfer line and provides the station 1 with flexibility in use.

  As mentioned above, this arrangement also allows for effective cooling of the transfer line.

  In fact, after a long waiting time, the transfer line can be heated. Cooling can cause problems on stations from the prior art.

  According to the proposed arrangement, the transfer line can be easily cooled in several ways.

  For example, at the very beginning of the fill, the line can be cooled using so-called "direct" cooling by transferring the cryogenic fluid to the tank 22. In fact, at the beginning of the filling, there may be a tolerance time window (often around 30 seconds), during which the tank 22 is filled with a gas that is not sufficiently cooled (above the target temperature). Sometimes. If the transfer line is short enough (eg less than 30 or 20 meters), the cryogenic hydrogen at the outlet of pump 5 can be sent directly to tank 22 after cooling the line during a tolerance window. .

  Temperature control of the temperature of the line may be performed using an open loop ("feed forward") type of correction or "cascaded" in response to the measured temperature 21 of the line (eg, the temperature of the gas in the line). Can be achieved. This means, in particular, that the opening set points for the valves 7, 8 are automatically controlled or forced to the value of the temperature measured downstream.

  According to another possible cooling mode (“so-called cold flushing”), the line can be cooled by a dedicated cooling gas stream that is not used to fill the tank 22.

  In fact, "direct cooling" may prove insufficient for longer transfer lines. Thereafter, it can be expected that a flushing line will be added. Thus, before filling the tank 22, the line can be flushed with cold hydrogen provided by the pump 5 and sent back to the buffer storage units 9, 10 by a flushing line (not shown for simplicity). .

  This flushing step can be performed once the tank is connected to the downstream end of the transfer line, while the user operates the interface before the actual filling. This can even be done in advance by detecting the arrival of the client / user / vehicle. This flushing step may require tens of seconds, depending on the length of the line and the ambient temperature.

Claims (16)

A filling device for filling a pressurized gas tank, especially a vehicle pressurized hydrogen tank,
The filling device,
A liquefied gas source (2);
A transfer circuit (3) comprising two parallel transfer lines each having an upstream end (3) linked to said liquefied gas source (2);
Each transfer line comprises a downstream end (4) intended to be detachably connected to the tank (22) to be filled;
Each of the two parallel transfer lines is
A pump (5),
An evaporation unit (6) for evaporating the fluid to be sent out;
A bypass branch (13) for bypassing the evaporation unit (6);
A set of distribution valves (7, 8) configured to control the flow of fluid delivered and distributed between said evaporation unit (6) and said bypass branch (13);
The filling device (1) further comprises a set of buffer storage devices (9, 10), the buffer storage device being parallel to each of the two parallel transfer lines via a set of valves (11-16). Filling device connected to.   The set of buffer storage devices (9, 10) comprises the evaporating unit (6) and the point of mixing between the fluid passing through the evaporating unit (6) and the fluid passing through the bypass branch (13). The filling device according to claim 1, characterized in that it is connected to each transfer line between them.   Filling device according to claim 1 or 2, characterized in that the set of buffer storage devices (9, 10) is connected to each transfer line via a respective expansion valve (15, 16). The set of distribution valves (7, 8) of each transfer line is located downstream of the evaporation unit (6) and upstream of the point of mixing with the fluid passing through the bypass branch (13). A first distribution valve (7),
The set of distribution valves (7, 8) comprises a second distribution valve (8) in the bypass branch (13). Filling equipment. The set of buffer storage devices (9, 10) comprises two or more buffer storage devices connected in parallel to each transfer line;
5. The device according to claim 1, wherein each buffer storage device is connected to a respective transfer line via a respective isolation valve. 6. Filling equipment. Said transfer circuit (3) comprises a connecting duct (17) linking said two parallel transfer lines to the outlets of two pumps (5);
Filling device according to one of the claims 1 to 5, characterized in that the connection duct (17) comprises a separation valve (18).   The filling device according to any of the preceding claims, characterized in that the two parallel transfer lines comprise at least one thermally insulated part (19).   The two parallel transfer lines may include at least one pressure sensor (20) and / or at least one temperature sensor (21) for measuring pressure and temperature respectively, in particular close to the downstream end (4). The filling device according to claim 1, wherein the filling device is provided. A method of filling at least one pressurized gas tank with a defined gas flow rate at a defined temperature to establish filling of the tank with a defined fill gradient,
A filling method, wherein the method uses a filling device according to any one of claims 1 to 8.   The filling method according to claim 9, wherein the gas flow rate is variable and changes over time. During at least a part of the filling operation, especially when the defined gas flow is greater than the maximum flow of the pump (5),
The gas flow transferred to the tank is provided by a first pump (5) and distributed between the evaporation unit (6) and the bypass branch (13); Method according to claim 9 or 10, characterized in that it is the sum of an additional gas flow rate provided by the set of buffer storage devices (9, 10). During at least a part of the filling operation, in particular when the defined gas flow rate is less than or equal to the maximum flow rate of the pump (5),
The gas flow transferred to the tank is provided only by the gas flow provided by the pump (5) and distributed between the evaporation unit (6) and the bypass branch (13). The method according to any one of claims 9 to 11, wherein   Filling the tank with a gas stream with the sum of the gas flows provided by the pumps (5) of the two transfer lines by transferring the gas stream from one transfer line to another. 13. The method according to any one of claims 9 to 12, comprising a step.   Cooling the transfer line prior to or at the beginning of filling of the tank (22), characterized in that the transfer line is relatively hot and passes through the evaporation unit (6). By managing the relative distribution between the gas and the relatively cold gas passing through the bypass branch (13), possibly additionally, the buffer storage device (9, 10) 14. The method according to any one of claims 9 to 13, comprising transferring the gas at a defined temperature controlled by managing the amount of relatively hot gas coming from the set.   The step of cooling the transfer line is controlled by controlling the opening of the distribution valve between the evaporation unit (6) and the bypass branch (13), and in some cases also an "open loop" (" Feed forward)) controlling the additional gas flow provided by the set of buffer storage devices (9, 10) according to type control and / or according to a control loop based on the temperature measured in the transfer line. The method of claim 14, wherein the method is performed by:   The step of cooling the transfer line comprises flushing to or out of a unit for collecting gas transferred at a controlled temperature controlled in the transfer line to be cooled. The method according to claim 14 or 15, characterized in that it comprises:

Images